Recent reports have indicated that chronic smoking of marihuana may depress the reactivity of the cellular arm of the immune response in man. Studies in laboratory mice demonstrated that delta-9-tetrahydrocannabinol (delta-9-THC) can suppress both humoral and cellular immune responses. It is the overall goal of this project to examine the relative influences of delta-9-THC, delta-8-THC, cannabinol (CBN) and cannabidiol (CBD) on humoral and cellular immune responsiveness in mice and to design specific immunotherapeutic regimens with these drugs for antineoplastic chemotherapy in experimental tumor systems. Delayed type hypersensitivity responses to sheep erythrocytes (SRBC) and oxazolone, and mixed hypersensitivity to methylated bovine serum albumin will be examined. Further, plaque-forming cell (PFC) responses to E. coli lipopolysaccharide (LPS) will be used to determine B-cell reactivity and PFC responses to Type III pneumococcal polysaccharide (SIII) will be used to determine alterations in T-cell regulatory activity. Information acquired from these systems will be used to design specific immunotherapeutic drug regimens to alter the growth of spontaneously arising C3H and Balb/cf3H mammary tumors. Information derived from these studies may be used to evaluate the therapeutic potential of this class of agents in tumor immunology and transplant surgery and may lead to a rational approach for evaluation of public health hazards by these drugs.